Stereo sound through one amp?

[DT4L]

hey all, just another amp question.. ive noticed on all the threads about amps there are people saying that it is crucial to have stereo sound for playing live ie. using two identical amps or using a PA.. my question is - if you have an amp with multiple inputs can you get stereo sound by pluging the left output and the right output of your keyboard into seperate channels on the amp?
i really no nothing about this stuff so please forgive me if its a stupid question.. thanks for any help.

[rlainhart]

If you plug the left and right outputs of your synth into a mono amp, you're going to get a mono signal, no matter what - you're just mixing the two channels down to one. To have stereo playback, you need at least two speakers driven by separate amps to maintain stereo separation.

There are self-contained stereo amps, with two speakers and two amp channels in one box, but even those are limited, since there's little stereo separation. For the best results, you need a reasonable amount of distance between the two speakers. A common setup is a pair of full-range PA cabinets on stands mounted to the left and right behind the keyboardist, driven by a stereo PA amp.